Abstract: Methane conversion to C2 hydrocarbons by low temperature plasma was studied in different reactors. The results showed that the product distribution varies with the change of the reactor type. In the reactor A and B, products contained more acetylene and less amount of ethylene and ethane, while in the reactor C and D, the main products were ethane and propane with little amount of ethylene and acetylene. The coke deposited on electrode had a high influence on methane conversion in reactor A, and a little effect on reactor C. The coke deposition conversed to CH4 via pure H2 discharge in those reactors. Through the products distribution, the reaction mechanism was deduced in different reactors. In reactor A and B, because of the high electron energy and density, methane was mainly decomposed to atom C and then it combined with itself or atom H to form C2 and CH, which directly formed the main product C2H2. In reactor C and D, methane was mainly decomposed to CH3 for the low electron energy and density and then CH3 combined with CH2 or itself to form C2H5, which were the precursor of C2H6. And the main byproduct, C3H8, was formed by coupling of C2H5 and CH3.